- related cleanup

See https://bugs.launchpad.net/zope2/+bug/713253/

Report success or failure (when known) of creating a new user with
the addzope2user script.

Added `addzope2user` script, suitable for adding an admin user directly to the root acl_users folder.

Factored out the `Products.ZCatalog` and `Products.PluginIndexes` packages into a new `Products.ZCatalog` distribution.

avoid pre-allocating the entire sequence, which adds unnecessary overhead in most cases.  instead use a dictionary to remember the already mapped sequence items.

fix `LazyMap` to avoid unnecessary function calls when not accessing items in order (fixes http://dev.plone.org/plone/ticket/9018)